The remodeling of bone is a dynamic process. Cells continuously lay down and resorb bone material. An imbalance in the activity of cells that lay down new bone (osteoblasts) and cells that resorb bone (osteoclasts) can result in serious, and sometimes even fatal, disorders.
Osteoporosis is a term used for a number of diseases of diverse etiology, all involving a reduction in the mass of bone per unit volume. Osteoporosis is the most common of the metabolic bone diseases. Twenty-five million people in the United States and more than two hundred million people worldwide are affected by osteoporosis. Osteoporosis is frequent among post-menopausal women and is an important cause of morbidity in the elderly. It commonly results in bone fractures, and death can be a frequent occurance in the months following fractures, particularly those of the hip in elderly individuals.
Osteopetrosis is a disorder involving an increase in the mass of bone per unit volume. Its incidence is rare compared to osteoporosis, but it typically is life threatening. Despite having multiple causes, a defect in bone resorption is always the underlying mechanism. In many instances, the disorder is inherited as an autosomal recessive trait and involves abnormal osteoclast function. Bone marrow transplants from normal donors have been attempted to restore normal osteoclast precursor cells, but this therapy has shown only limited success.
Present treatments for osteoporosis and osteopetrosis are inadequate.
There exists a need to influence favorably the bone remodeling process to treat osteoporosis and osteopetrosis. There also exists a need to identify the gene(s) responsible for osteopetrosis and to provide a genetic therapy for treating osteopetrosis.
An object of the invention is to provide compounds that desirably influence the bone remodeling process.
Another object of the invention is to provide therapeutics for treating osteoporosis.
Another object of the invention is to provide therapeutics for treating osteopetrosis.
Still another object of the invention is to provide diagnostics and research tools relating to osteoporosis and osteopetrosis. These and other objects will be described in greater detail below.